This invention relates generally to mass mail handling equipment. More particularly, this invention relates to an improved apparatus for taking a series of flat articles such as envelopes, orienting them, and then stacking the articles in groupings.
In the high volume mail industry, in both U.S. First Class and Third Class mail, envelopes are filled with various letter pieces using automated mail inserters. For example, U.S. Pat. Nos. 5,029,832 and 5,211,384 disclose an in-line inserter device having envelope and feeding assemblies, an envelope inserting station, a sealing and stacking assembly, and various diverter stations.
Mass-mailing equipment has become very diverse in its functions. For instance, inserting equipment transports envelopes along an inserting track while various types of inserts are automatically inserted into the envelopes. The envelopes are normally transported to another piece of equipment that automatically seals the envelopes, weighs them and affixes postage. Still additional equipment automatically reads the zip codes or zip code indicia on the envelopes and indicates zip code breaks in the envelope groups for zip code presorting. This allows the user to take advantage of lower postage rates. Other mass-mailing equipment may include remittance processing equipment and zip code sorting equipment.
Customers utilizing mass-mailing equipment may have differing needs and requirements. Therefore, mass-mailing equipment is generally designed for one specific function. Each piece can then be connected by conveyor or other transport means to additional mail processing equipment so that a customized system can be assembled. One problem with this approach is that adjacent mail processing equipment may require the envelopes to be oriented in a position which is different from the discharge device of the preceding equipment. This necessitates transition conveyors or re-orientation devices.
For example, most mail processing inserting equipment in use today moves the envelopes along a track with their faces (the addresses) face down and the flaps extended with the back of the flaps up during the insertion mode. The envelopes, as they leave the inserting machine, may have the flaps moistened and sealed before exiting the inserting machine. If the envelope is then going to have postage applied, it must be turned over 180 degrees so that the postage can be affixed to the face of the envelope. Other operations may require the envelope to be turned 90 degrees.
One such stacking apparatus is disclosed in U.S. Pat. No. 4,705,157. Here, a device is disclosed for turning envelopes 90 degrees as the envelopes are moved forward through the device from an entrance location to an exit location using two endless belts adjacent to one another. The envelopes are ultimately stacked once they leave the exit location.
Currently, many inserters simply eject the filled envelope onto a short flat conveyor, allowing the envelopes to free float on the conveyor. This causes the possibility that the zip order of the envelopes will get mixed up, the possibility of envelopes becoming disorderly and difficult to quickly pick up, and the possibility of envelope flaps popping opened prior to proper glue drying. Additionally, this method is an inefficient use of conveyor space, allowing only a short amount of time before the conveyor becomes full. This requires the increased attention from an operator. Often, an operator is forced to shut down the entire machine so that he or she can catch up with the emptying of the conveyor. Obviously, this drastically reduces the overall throughput of envelopes.
These mail inserters may run at speeds, for example, from several hundred filled envelopes per hour to approximately 18,000 envelopes per hour. These speeds have created a need on the end of the inserters to collect the filled envelopes in such a way as to allow the operator to load them into mail trays or other forms of storage quickly and efficiently. In addition, since these envelopes are often prearranged in special zip code order, this order must be maintained by the operator and then separated into different trays depending on these zip code groupings.
This area has proven to be the xe2x80x9cbottleneckxe2x80x9d of the mail insertion process. Many times, the operator has a difficult time keeping up with the inserter. Additionally, the envelopes are not presented in such a way that the zip code breaks can be read easily. The operator may develop fatigue, possibly even carpal tunnel syndrome, because of excess handling of envelopes. One means to assist here is the inclusion of an envelope stacking apparatus at the end of the system to secure the sorted mail pieces in a stacked position to facilitate the orderly removal of the processed mail pieces from the system.
One area of difficulty with envelope stacking apparatus is the high likelihood of jamming and high complexity of various apparatus presently available. For example, one method used to handle envelopes after inserting, as provided in U.S. Pat. No. 4,903,955, is a conveyor that turns the envelopes on edge and horizontally stacks them using a wire auger, in the form of an enlarged corkscrew. Shortcomings of this method include the requirement for a complex algorithm to keep an open part of the auger exposed to the incoming envelope in addition to a possible short life of a spring clutch used to turn the auger.
U.S. Pat. No. 4,705,157 provides an article turning apparatus for turning envelopes to an on-edge position and discharging those envelopes for stacking on a conveyor. Two belts receive an envelope in a horizontal position and turn it ninety degrees to an on-edge position. This patent also discloses a segmented roller that assists in stacking the envelopes vertically. However, here, the segmented roller turns continuously and the segmented roller is adapted to strike the surface of the last discharged envelope to create a pulsing force. This system does not prevent the jamming of an incoming envelope.
U.S. Pat. Nos. 5,485,989 and 5,201,504 do handle higher speed inserters and offset the stack at a zip break. However, the conveyors disclosed in these patents are complex and costly and require that the zip break signal be given to it via electronic communication from the inserter.
PCT Serial No. PCT/93/02731 discloses an apparatus for stacking sheet like articles having a discharge magazine that includes conveyor belts and a document stop element for receiving articles on edge. A sensing means indexes the conveyor belts to allow envelopes to be stacked on a magazine.
One feature of many on-edge stacking conveyors is the ability to offset the registered edge of a horizontal envelope stack so as to easily identify the zip code change or count to the offloading operator. This is typically accomplished by a printing, such as a zip code, bar code, optical mark, etc., on the envelope, read by an electronic reading device, as the envelope enters the on-edge stacking apparatus. This data is then used to index an offsetting device that causes the front perimeter edge of the envelope stack to create an offset from the envelopes previously received in the stack. That is, a series of envelopes is first stacked against a register wall. When a new zip code break is read, the offset device causes new envelopes to offset by a small amount. The result is an indexed stack with zip code breaks easily identified. In present systems, after a set of envelopes has been offset by the offset device and a new zip code break is read, the next set of envelopes coming in no longer is required to be offset. However, the first incoming envelope of a new set may drag the prior, offset, envelope back to the register wall due to frictional drag. This occurs particularly when the offset device is withdrawn too soon. This may be overcome by delaying, for example, via software, the moment when the parallel wall of the offset device is retracted to several inches before the new envelope gets to the offset device. This solution is only partially successful because the retraction of the offset device must be started early because the front lip of the offset must be clear before the new envelope passes it. Because there are still several inches of travel for the incoming envelope, there is still some frictional drag of the prior envelope.
Accordingly, it would be desirable to provide an improved on-edge stacking apparatus for stacking a plurality of flat articles on edge which overcomes the disadvantages of the prior art.
It would further be desirable to provide an improved on-edge stacking apparatus for stacking a plurality of flat articles such as envelopes on edge that operates at high speed.
It would further be desirable to provide an improved on-edge stacking apparatus for stacking a plurality of flat articles such as envelopes on edge that operates without jamming.
It would further be desirable to provide an improved on-edge stacking apparatus for stacking a plurality of flat articles such as envelopes on edge that provides a means to separate different groups of the articles.
It would still further be desirable to provide an improved on-edge stacking apparatus for stacking a plurality of flat articles such as envelopes on edge that re-orients from a flat position to an upright, on-edge position.
It would further be desirable to provide an improved on-edge stacking apparatus for stacking a plurality of flat articles such as envelopes on edge that does not require an operator to shut down the apparatus on a regular basis so that the operator can catch up with the emptying of the stacked articles.
It would further be desirable to provide an improved on-edge stacking apparatus for stacking a plurality of flat articles such as envelopes on edge that does not require a complex algorithm to operate causing potential jamming and failure of the apparatus.
It would further be desirable to provide an improved on-edge stacking apparatus for stacking a plurality of flat articles such as envelopes on edge that provides a means to offset a horizontal envelope stack to mark zip code changes.
It would further be desirable to provide an improved on-edge stacking apparatus for stacking a plurality of flat articles such as envelopes on edge that maintains pressure on the envelopes in the stack to allow time for the flap glue to dry.
It would further be desirable to provide an improved on-edge stacking apparatus for stacking a plurality of flat articles such as envelopes on edge where the articles are moved from a flat position to a horizontal position, either clockwise or counterclockwise using a single belt.
Many other attendant features of this invention will become readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings.
A stacking apparatus for stacking a plurality of flat articles on edge is provided. Each article has a front perimeter edge and two faces. The stacking apparatus receives each of the flat articles as each article enters the stacking apparatus moving in a direction generally parallel to the faces of each article. The stacking apparatus includes a discharge magazine for sequentially receiving and stacking the flat articles face-to-face in an on-edge stack. The discharge magazine includes an article inlet and an article edge receiver. The article edge receiver includes a non-offset position and an offset position. In either the offset position or the non-offset position, the front perimeter edge contacts the article edge receiver to align the front perimeter edge of each article as the articles enter the stack. The discharge magazine further includes an article face receiver wherein a face of one of the flat articles abuts the article face receiver. The article edge receiver has a register wall, wherein when the article edge receiver is in the non-offset position, each front perimeter edge contacts the register wall to align the front perimeter edge of each article. The article edge receiver also has a segmented rotational offset disk to provide the offset position. The segmented rotational offset disk has a rotational axis and at least one cut out segment where the cut out segment has a planar stop edge surface parallel to the rotational axis. The cut out segment is rotatable from an article receiving position to an article bypass position. When the cut out segment is in the article receiving position, the planar stop edge surface is at substantially a right angle to the two faces of the article and the planar stop edge surface is adapted to receive the front perimeter edge of each article. When the cut out segment is in the article bypass position, the article edge receiver is in the non-offset position such that the segmented rotational offset disk allows the front perimeter edge of each article to bypass the segmented rotational disk.
The article face receiver is preferably moveable along a conveyor to provide additional space, as required, for articles while providing a compressive force to the stack of articles.
A continuously rotating additional roller adjacent the segmented roller may be included to assist in driving each article to the article edge receiver.
The article stack offsetter may be adapted to offset the articles at specific article counts.
The article stack offsetter may be adapted to offset the articles when an electronic signal is received.
Preferably, the cut out segment is pie-shaped.